CKEditor 5 ESLint plugins

A set of plugins used by the CKEditor 5 team for Eslint

By default this plugin is added to our eslint-config-ckeditor5 preset.

Usage

npm i --save-dev eslint-plugin-ckeditor5-rules

Configure ESLint using the following contents:

import { defineConfig } from 'eslint/config';
import ckeditor5Rules from 'eslint-plugin-ckeditor5-rules';

export default defineConfig( [
    {
        plugins: {
            'ckeditor5-rules': ckeditor5Rules
        },
        rules: {
            'ckeditor5-rules/no-relative-imports': 'error',
            'ckeditor5-rules/license-header': [ 'error', {
                headerLines: [
                    '/**',
                    ' * @license Copyright (c) 2003-2025, CKSource Holding sp. z o.o. All rights reserved.',
                    ' * For licensing, see LICENSE.md or https://ckeditor.com/legal/ckeditor-oss-license',
                    ' */'
                ]
            } ]
            // ...
        }
        // ...
    }
] );

Rules

The list of all ESLint rules published in eslint-plugin-ckeditor5-rules package is documented on https://ckeditor.com/docs/ckeditor5/latest/framework/contributing/code-style.html#ckeditor-5-custom-eslint-rules.